The DVD-Video format for optically readable discs is defined in the DVD Specifications for Read-Only Disc, part 3: Video Specifications (version 1.0, August 1996). Relevant parts therefrom are being disclosed in for instance European Patent Application EP 724 264 and U.S. Pat. No. 5,784,528, respectively document D1 and D2 in the list of referred documents that can be found at the end of this description. Both documents are incorporated by reference herein.
The DVD-Video format as defined in the above mentioned Specifiations for READ-Only Disc and disclosed in D1 and D2 was created for storing movies and other video content on read-only DVD media. Some of the features of the DVD-Video format make it less suitable for real-time recording applications.
However, it is desirable to create and record video streams and associated data structures on rewritable media in real time which are should preferably be almost identical to the structures defined in the DVD-Video format. Such rewritable discs should be play back compatible with the majority of the installed base of consumer DVD-Video players. The method according to the invention describes a novel and inventive format for DVD-Video compatible real-time recording of video streams, referred to hereinafter to as Real Time DVD Video Recording or shortly DVD-Video Recording. The format defined is intended for home video recording on an optical medium which is playback compatible with DVD-Video players.
The above-mentioned DVD-Video format demands that data for a VTS be allocated contiguously. This gives all kinds of problems when part of the data is overwritten with new recordings:
The DVD-Video format allows an arbitrary numbering of Video Titles (VT) within a Video Title Set (VTS). For instance such as the sequence of Video Titles: VT1, VT3, VT2 . . . . Overwriting for instance Video Title VT 3 with a new and larger Video Title VT4, will result in overwriting also Video Title VT2. This would appear strange to a user, employing a Video Title menu listing the Video Titles in consecutive order: VT1, VT2, VT3, . . . . Such a sequence would be changed into a sequence like: VT1, X, VT4, . . . with X denoting a deleted Video Title.
Thus, when partial overwrite is one of the features, the user model of the recording medium becomes complicated.